So now for the electrical, I needed to have the siding on because I was going to send two LBs (elbows) through the back wall into the subpanels. The main service is 200 amps and the subs are 70 amps each. I plan on having a 230 outlet in each bay for a MIG / TIG welder and to run a 5hp compressor. The rest will be used for heating, lighting and hand tools.
If you look was up there the building is essentially 3 areas separated by the columns and girders. I called the truss designer early in the build to ask if I could drill through the columns to pass romex through. The answer was no... the columns and girders are treated like trusses, you cannot penatrate them without the designers permission. On each end of the girder, there is a PSL column holding it up. From memory, the reaction of the girder on the PSL is 28,000lbs with a full snow load (85psf). So by drilling through the PSL, you are reducing the cross section... I probably could have done something, but we didn't need any questions down the road... for quicky math, the PSLs are 5x7 or 35 square inches... their compressive load is 2500 psi... so they can hold 87,000lbs each! But then again 85 psf of snow is about 15 feet tall, and on a steel roof it probably never happen.
So I decided that I would have the one main service panel and two sub-panels... just needed to figure out how to feed them.
One solution would have been to feed each subpanel under the concrete, but I didn't want the sweeps to come out of the floor and into the wall... doesn't matter where you put them, sooner or later they will get in the way or get busted by something heavy and rolling.
The other solution was to trench outside and feed them, so that what I did. From the main service, I went down to an LB, then outside to another LB and went around back.
This LB is joined to the LB on the inside under the main service.
This is the run down the side of the building.
Then up to a JB (junction box) and to the other sub (panel)
Over Thanksgiving weekend, we pulled the feeders to the subs and hooked them all up, so I have power in the other 2 bays of the barn.
In NH you are allowed to do your own electrical work without a liscense. That doesn't exempt you from the NEC, but if you know what your doing and have someone to ask questions of you are all set. The subs are fed with #4 aluminum wire (rated for 75 amps). I would have still needed #4 copper (at 85 amps), so it was cheaper to run aluminum.
Blair